DESCRIPTION: The goal of this revised project is to demonstrate the value of studying non-routine events (NRE) during actual patient care in the field of anesthesiology. An NRE is defined as any event that is perceived by care providers or skilled observers to be unusual, out of the ordinary, or atypical. NRE thus represents perturbations and smooth expert processes and may provide insight into potential system faults, allowing study of process as well as outcome of care. Using anesthesia as a model of a structured medical work environment, the investigators will collect prospective and retrospective data on non-routine events in the perioperative period, develop a useful classification of such events, and relate them to clinical outcomes. This research will ascertain whether rigorous characterization of the factors contributing to the occurrence of, and recovery from, NRE facilitates understanding what distinguishes safe versus unsafe medical practice. Clinical experience is hypothesized to be a principal factor influencing the nature and outcome of NRE. Clinical workload, situation awareness, production pressure and human error are hypothesized to be independent predictors of NRE incidents and outcome. Direct observation and video taping of NRE during actual patient care will provide behavioral task analysis and measurement of workload and situation awareness. NRE will also be identified by systematic query of clinicians in the recovery room, by a confidential reporting system, and by chart screening. Structured interviews will examine providers knowledge and decision processes with regard to NRE ideology, management and factors influencing outcome. NRE-containing video tapes will be reviewed by providers and by experts. Each NRE will be categorized and logged in a database. Complementary multivariate analysis techniques will test the a priori hypotheses and delineate other predictors of NRE frequency, type, and outcome. In year 3 the investigators will begin to apply these methodologies of identification and categorization of NRE in the post-anesthesia and intensive care units to delineate how this approach will generalize to a non- OR setting. The proposed studies, while yielding applied knowledge of specific ways to reduce medical error and improve clinical care, also address more fundamental issues of human cognition and the nature of expertise.